Last Updated September 2, 2026

FDA-Authorized and Conditionally Approved Animal Drugs for New World Screwworm

New World screwworm larvae, or maggots, are typically found in pre-existing wounds or mucous membranes and cause NWS myiasis. This guide provides an overview of FDA-authorized animal drug tools for treating and preventing New World screwworm and highlights key treatment and prevention information for livestock producers, owners of companion animals and veterinarians.

See the FDA’s webpage for more information on the regulation of animal drugs.

Responsible Use

• Overuse or misuse of antiparasitic drugs can contribute to reduced effectiveness and the development of parasite resistance.
• These products should be used cautiously and only as part of a broader parasite control strategy.
• Vigilance in wound care, frequent surveillance, rapid reporting and enhanced management practices are critical complements to using treatments.

Guidance for Producers, Pet Owners and Landowners

• Inspect animals frequently and provide prompt wound care. Monitor newborns closely.
• Report suspected New World screwworm cases immediately.
• Work with your veterinarian to determine appropriate preventatives and treatments.

Reporting

If you suspect a case in a companion animal, contact your veterinarian immediately. Oklahoma Department of Agriculture, Food and Forestry (ODAFF) must be notified of all suspected and confirmed cases of New World screwworm. Cases can be reported to ODAFF at (405) 522-6141.

Contact the Oklahoma Department of Wildlife Conservation (ODWC) at (866) 487-3297 for suspicious wildlife.

Treatments and Preventatives

The FDA's Center for Veterinary Medicine is working with drug sponsors, federal and state partners, and international regulators to understand options for U.S. veterinarians to treat New World screwworm effectively and safely. The FDA continues to review and announce conditionally approved and authorized animal drug options for New World screwworm on its Animal Drugs for New World Screwworm webpage. Download a PDF of the full list from the FDA website.

Remember: Always follow label directions and veterinary guidance. Treatments support response efforts but do not replace prevention or reporting.

Livestock Treatments and Preventatives

* FDA Emergency Use Authorizations (EUAs) are notated with an asterisk (*).
^ FDA Conditional Approvals are notated with a caret (^).

* Bimectin (ivermectin) injection
Indication: Prevents NWS in cattle

* CLiK Extra (dicyclanil topical suspension) wound spray
Indication: Prevents NWS in sheep, cattle, goats, swine, camelids and the following captive and captured wildlife species: cervids, American bison, bighorn sheep and Sonoran pronghorn.

* Dectomax/Dectomax-CA1 (doramectin injection)
Indication: Treats and prevents NWS in dairy cattle (lactating dairy cows, dry dairy cows and replacement dairy heifers 20 months of age and older) except for calves that will be processed for veal, horses one year and older, swine, sheep (except for lactating sheep) and deer.

^ Dectomax-CA1 (doramectin injection)
Indication: Prevents and treats NWS in cattle, including reinfestation for 21 days.

^ Exzolt Cattle-CA1 (fluralaner topical solution)
Indication: Prevents and treats NWS infestations in beef cattle two months of age and older and replacement dairy heifers less than 20 months of age.

* F10 Antiseptic Barrier Ointment with Insecticide (benzalkonium chloride, polyhexanide and cypermethrin topical ointment)
Indication: Prevents and treats NWS infestations in cattle, horses, minor species of hoof stock, raptors and other wild birds, pet birds and captive wild, exotic and zoo mammals.

* F10 Antiseptic Wound Spray with Insecticide (benzalkonium chloride, polyhexanide and cypermethrin topical solution)
Indication: Prevents and treats NWS infestations in cattle, horses, minor species of hoof stock, raptors and other wild birds, pet birds and captive wild, exotic and zoo mammals.

* Ivomec (ivermectin) injectable solution
Indication: Prevents infestations caused by NWS when administered within 24 hours of birth, at the time of castration or at the appearance of a wound in cattle, except for female dairy cattle producing milk for human consumption and calves that will be processed for veal.

* Ivermectin Liquid for Horses (ivermectin oral solution)
Indication: For short-term prevention of NWS infestation when administered within 24 hours of birth or at the time of initial wound care in horses.

* Negasunt Powder (coumaphos, propoxur and sulfanilamide topical powder)
Indication: Prevents and treats NWS infestations in cattle, swine, goats, sheep, horses, donkeys, domestic hybrid equids and captive wild, exotic and zoo mammals.

Companion Animals Treatments and Preventatives

* Credelio (lotilaner) chewable tablets
Indication: Treats NWS in dogs and puppies.

* Credelio CAT (lotilaner) chewable tablets
Indication: Treats NWS in cats and kittens.

^ Credelio Quattro-CA1 (lotilaner, moxidectin, praziquantel and pyrantel chewable tablets)
Indication: Treats infestations caused by NWS in dogs and puppies weighing 3.3 pounds or greater and 8 weeks of age and older.

* NexGard (afoxolaner) chewable tablets
Indication: Treats NWS infestations in dogs.

* NexGard COMBO (esafoxolaner, eprinomectin and praziquantel topical solution)
Indication: Treats NWS myiasis in cats.

* Nitenpyram Tablets (nitenpyram)
Indication: Treats NWS myiasis in dogs, puppies, cats and kittens 2 pounds of body weight or greater and 4 weeks of age and older.

*Simparcia TRIO (sarolaner, moxidectin and pyrantel chewable tablets)
Indication: Treats NWS in dogs and puppies.

Veterinarians

View helpful information for veterinarians on the FDA website.